Electric drum or other percussion instrument



A. J. GREEN 3,509,264

ELECTRIC DRUM OR OTHER PERCUSSION INSTRUMENT" April 28, 1970 v FiledDec.

U Q @Q PREMIPLIFIER mvENroR Allen .1 Green BY ATTORNEY United StatesPatent 3,509,264 ELECTRIC DRUM OR OTHER PERCUSSION INSTRUMENT Allen J.Green, 1514 44th St., Brooklyn, N.Y. 11219 Filed Dec. 29, 1967, Ser. No.694,451 Int. Cl. Gh 3/00, 1/00; G10d 13/02 U.S. Cl. 84-1.15 10 ClaimsABSTRACT OF THE DISCLOSURE The electric pickup for the instrument hastwo relatively movable parts, a coil and a magnet. One part is securedby epoxy cement to, and vibrates with, a vibratory member such as theskin of a drum or the disc of a cymbal. The other part is secured to arelatively fixed element of the instrument. In use, the weak signalinduced in the coil is led to a preamplifier and amplified.

This invention relates to the means foramplifying the sounds of certainmusical instruments such as drums, cymbals, gongs, bells and otherpercussion instruments.

The noise resulting from mechanical impact of the striking element uponthe vibratory element of the instrument would, especially if amplified,in many instances interfere with the sound produced by the merevibration of the vibratory element such as a drum skin, a cymbal disc orgong disc, or the campanulate element .of a bell. The frequency of thedesired sound waves to be produced by the instrument may also be alteredor distorted. Furthermore, the force of such impact, as well as thevibration of the instrument, tend to loosen and ultimately detach anypickup part attached by any means to the vibratory element.

It has been found, that any pickup part applied to a drum skin shouldhave minimum weight and should be so attached that loosening anddetachment thereof under the forces of use, does not occur. The pickupshould also screen out mechanical noises but should faithfully reproduceand amplify the pure tone of the vibratory element. The output signal ofthe pickup may-properly be quite weak, since known preamplifiers towhich the signal may be led, usually accept a low impedance input.

The pickup of the present invention meets all the requirements aboveoutlined and in addition has few parts, is simple, inexpensive, notlikely to get out of order, and easily attached to percussioninstruments of various types.

The various objects of the invention will be clear from the above andfrom the description which follows and from the drawings, in which- FIG.1 is a top plan of one type of a conventional drum to which theinvention has been applied, part of the drum skin being omitted toreveal the underlying parts.

FIG. 2 is a fragmentary elevational view of the drum partly in sectionand showing the connection to a pre* amplifier.

FIG. 3 is an enlarged fragmentary vertical sectional view of the drumand pickup therefor, the arrows showing the general direction of thevibratory movement of the drum skin.

FIG. 4 is a partial verticalsectional view of a loosely mounted cymbal,showing a modified form of the pickup.

FIG. 5 is a similar fragmentary view of a firmly mounted cymbal andpickup therefor.

In general, the pickup converts the percussion instrument to a soundamplifying device akin to a microphone, thereby permitting directamplification for recording purposes or for the entertainment of largeaudiences without the need for external microphones and relativelyexpensive pickup installations. The pickup comprises magnet P 64 Ice3,509 2 means preferably in the form of a permanent magnet and coilmeans of various possible forms and arrangements but secured firmly, oneof the means to a vibratory element of the instrument and the othermeans to a fixed part. The coil means is arranged in inductive relationto the magnet means and in sufficient spaced relation thereto topreventcontact thereof in use when the vibratory element is struck with themaximum force customarily used when playing the instrument. Similarly,since the coil means preferably has a ferric core and would be attractedby and retained by the magnet means against retraction to the properoperative position of the coil means, the spacing between the two meansand the strength of the magnet means should be such as to avoid suchretention.

In the practical embodiment of the invention shown in FIGS. 1-3, thedrum 10 may vary greatly in type and in size, but the same pickup 11 maybe used despite such variations. To the tightened drum skin 12, whichconventionally constitutes the vibratory element of the drum, issuitably secured the coil 13, the skin being of suflicient area and wideenough to permit such attachment. It will beunderstood however, that inthe case of other percussion instruments having vibratory elements ofsubstantial width, rigidity and strength, the relatively heavy magneticmeans of the pickup instead of the coil means may be fixed to thevibratory element in such a manner as .to vibrate as a unit therewith,as in FIGS. 4 and 5 wherein the magnet is affixed to the cymbal disc.

For the purpose of illustration, the drum skin 12 has been shown asclamped to the drumside or cylinder by means of a clamping ring 14, butit should be understood that the construction of the drum is of nosignificance in the operation of the pickup, provided that'the drum hasavibratory element and a relatively fixed element as in most percussioninstruments.

To construct a coil structure substantially impervious to mechanicalshock resulting from use of the instrument, fine enamelled wire ispreferably wound in a number of layers, such as three, around aferriccore 16. Strip material of rectangular cross section, and known astransformer leaf, has been found satisfactory for the core. Between thelayers of wire turns is interposed a layer of suitable dielectric orinsulating strong plastic cementsuch as epoxy resinous cement oradhesive which bonds the core, the turns and layers of wire togetheragainst possible dislocation and unwinding under the stresses resultingfrom percussion. The plastic quick setting epoxy resin and hardener soldunder the trademark Duro by The Woodhill Chemical Corporation ofCleveland, Ohio, has been found to be adequate for the purpose. The sameepoxy plastic cement is preferably used for encapsulation not only ofthe coil and its core to fill all interstices and spaces therein butalso for encapsulation of the coil leads to the shielded cable 17 whichconnect the coil to a suitable pin plug receptacle 18. Said receptacleis fixed to the drum side in any suitable manner and conductors extendtherefrom to a preamplifier 19.

As has been indicated, it is highly advisable in View of the severemechanical forces inherent in the operation of the drum and which tendto loosen the coil, that suitable means be employed to affix andstrongly hold the coil to the drum skin. Such means should also resultin a rigid attachment of the coil in a manner to transmit faithfully thesound vibrations of the skin to the coil without being so excessivelythick as to distort the drum tones or to transmit unwanted sounds suchas the sound of impact of the striker such as a drum stick, upontheskin. By bending the core member 16 into an L-shaped form, the flangeor leg 20* thereof outstanding from the core proper of the coil, becomesan attaching bracket member and may readily be secured to the under faceof the drum skin Patented Apr. 28, 1970' by means of a patch 21 ofsubstantial area of epoxy cement of the type above mentioned andapproximately inch thick thereby to suspend the coil from the skin. Thepatch extends past the leg 20 on both sides and covers an area of aboutone inch square as best seen in FIG. 1.

The magnet 22 constitutes the remainder of the pickup and is secured toa relatively fixed part of the drum such as the drum side 23, againstwhich the skin is clamped. While any suitable means may be employed tofix the magnet in place, a layer 24 of the epoxy cement mentioned aboveis preferred. The gap between the pole of the magnet and the coil 13 ispreferably about inch for small drums. It will be understood that saidgap lessens when the skin is depressed by a blow, and that the coilconsequently swings somewhat closer to the magnet at that time, but notenough to be drawn into contact with the magnet and to stick theretoagainst retraction on the return of the skin to its normal position. Asseen in FIG. 3, the skin vibrates vertically when struck, so that thecoil vibrates therewith and with its core 16 as a unit and in the planeof said core and in the magnetic field to induce the desired signal.

In the form of the invention shown in FIG. 4, the cymbal disc 25 isprovided with a central aperture 26 larger in diameter than that of thereduced extension 27 passing through the aperture and projecting fromthe end portion of the relatively fixed disc-supporting rod 28. The discnormally rests on the shoulder 29 loosely at the junction of theextension 27 with the remainder of the support rod. The nut 30 on theextension adjustably limits the upward movement of the disc underimpact. As shown, the coil 31 is fixedly mounted on the upper part ofthe rod 28 in the field of the annular magnet 32, said rod constitutingthe core of the coil and being integrated with the disc support. Anysuitable means may secure the magnet to the disc 25 concentrically ofthe coil 31, but as shown, a layer 33 of epoxy cement is used for thatpurpose. The magnet therefore vibrates with the disc as a unit andrelatively to the core 28 to induce the required signal.

In FIG. 5, a central aperture in the disc is of about the diameter ofthe threaded extension 27, and the nut 30 holds the cymbal disc firmlyagainst the shoulder 29. Obviously, the pickup may be applied to cymbalsof various constructions, as well as to other percussion instruments, solong as the general principles of the invention are followed. The magnetmay be attached to a relatively fixed part of the instrument or to thewide vibratory part, while the coil is attached to the other of the twoparts and in the magnetic field, care being taken to so arrange the coiland the magnet that a sufliciently large gap is provided between thecoil and the magnet ,and that the attachment thereof, by whatever means,though preferably by epoxy resin, is strong and durable.

While certain specific forms of the invention have herein been shown anddescribed, various obvious changes may be made therein and which neednot be detailed, without departing from the spirit of the inventiondefined by the appended claims.

I claim:

1. The combination with a percussion musical instrument such as a drum,cymbal, gong, bell or the like, said instrument being provided with arelatively wide vibratory percussion element adapted to be struckdirectly and repeatedly with a striker and with a fixed element fixedrelatively to the percussion element, of

a pickup for the instrument adapted effectively to resist damage anddisplacement under the blows of said striker, said pickup comprisingmagnet means fixed to one of said elements, and coil means having awinding and a metallic core bonded to said winding, said coil meansbeing fixed to the other of said elements in inductive relation to themagnet means, whereby on movement of one of said means relatively to theother when the percussion element is struck, an electric signal isgenerated in the coil means.

2. The combination of claim 1, the magnet means being completely outsideof the coil means and in sufficient spaced relation thereto to preventmutual contact thereof in use and also to prevent magnetic retention ofthe coil means by the magnet means on maximum movement of the percussionelement under a severe blow and consequent substantial relative movementof the coil means and the magnet means toward each other.

3. The combination of claim 1, a layer of epoxy cement interposedbetween and firmly securing one of said means to the inner surface ofthe percussion element and encapsulation of epoxy cement completelyencasing the coil means including said core, the core passing completelythrough the winding.

4. The combination of claim 1, the magnet means being a permanentmagnet, the core of the coil means being an L-shaped strip, one leg ofthe core carrying the winding, the other leg being bare and encapsulatedin epoxy cement and secured thereby to the inner surface of thepercussion element.

5. The combination of claim 1, the instrument being a cymbal including acymbal disc, one of said means being annular and secured to the innerface of the disc and surrounding the other of said means, the other ofsaid means being secured to the fixed element concentrically of theannular means.

6. The combination of claim 1, the instrument being a drum, the magnetmeans being a permanent magnet arranged completely outside of the coilmeans, the percussion element being the skin of the drum, the entirecoil means including said core being affixed directly to the inner faceof the skin by a layer of epoxy cement approximately inch thick, thecoil means being encapsulated in epoxy cement to fill all spaces thereinand being movable as a unit with the skin relatively to the magnet whenthe skin is struck.

7. The combination of claim 4, the winding and the core of the coilmeans being encapsulated in epoxy cement, and the bare leg of the coresupporting said coil means in substantial spaced relation to and beyondthe magnet.

8. The combination of claim 1, the instrument being a drum, thepercussion element being the skin of the drum, the magnet means being apermanent magnet, the coil means having an L-shaped ferric core, one legof the core carrying the coil the other leg being bare and encapsulatedin adhesive means and secured thereby to the inner surface of the skinbetween the center of the skin and the side of the drum in sulficientspaced relation to the coil means to prevent magnetic retention of thecoil means in use of the drum, the thickness of the adhesive means forthe bare leg of the core being insufiicient to interfere with thevibration of the skin.

9. The combination of claim 5, said one of said means being the magnetmeans, and the other of said means being the coil means, the fixedelement constituting a support for the disc and also the core of thecoil means.

10. For use in a percussion musical instrument provided with a vibratorypercussion element of substantial length, width and area having asurface exposed to a forcible blow by a striker and also having arelatively fixed supporting element for the percussion element,

a pickup comprising a coil encapsulated in epoxy cement and having acombined metallic core and support for the coil bonded thereto, saidcore passing completely through the coil and being adapted forintegration with a selected one of said elements to affix the coildirectly to said element, and a magnet completely outside of and insufiicient spaced relation to the coil and the core to prevent magneticretention of the coil by said 6 magnet, said magnet being adapted to be86- 2,988,946 6/1961 Ritchie 841.15 cured to the other of said elementsby epoxy 3,018,680 1/1962 Paul 841.15 X

cement.

HERMAN KARL SAALBACH, Primary Examiner References Cited 5 T. J. VEZEAU,Assistant Examiner UNITED STATES PATENTS 2,900,453 8/1959 Cammack s4-411x 2,938,420 5/1960 Kunz s4 1.15 s4 1.01, 411, 462

